[Oddjob83]

I started welding some AL posts today, about 14 of them and more likely 50 more to come. Everything started fine, and my first pieces were pretty good and all went according to plan. then things started to fall apart, not literally, but the welds looked like crap. First i went through like 4 tips, and before today i was using the same tip we've had for the last 4 years. I would get random burn backs, or ( I think it was arc blow) the spray would just start sticking to one side of the weld. I had figured the contact tip was over heating as it was turning purple, so . . . . I would dunk it in water. it cooled it down and I'd feed out a few inches of wire, but then the next weld would be horrible so i stopped doing that.

Other than my problems, I am just not sure what to make of my welds, like are they supposed to look like this? is a jet of black soot at the end normal? there was was lot of starts and stops and tight angles. it is 3"x1.5" 6061 channel on an unknown 1/4 6"x6" plate with 3/64 4043 wire






the welds are strong, i took a sledge hammer to a sample in the vice and wrecked the channel instead and no cracks in the weld at all.

[Otto Nobedder]

This is now production work, and everything gets hotter. Try .052 tips. When the 4043 gets hot it will bind in an .045 tip, and 3/64 is .046-something. This may help eliminate random burn-back.

The soot is a more interesting question. Have you changed bottles recently? Is it possible you have a new spatter-burn in the gas hose (leak)? Did this possibly start with a wire-change, where the wire may have some minor surface contamination?

Just looking at the pictures, if all this is new, some part of the equation has changed, and you can rule the changes out one by one.

Steve S

[Oddjob83]

the soot has been common for me only at the end of the weld I don't get any around the sides of the weld anymore. I wasn't sure if that was waaaay to much soot. the wire has been sitting in the spool gun for a few months so chances are it has oxidized pretty good. but i also replaced it at lunch and got the same performance with a new one. I'll have to try some .054 tips. Also about every other weld when i start despite always cutting like and inch of of wire every time, I get a loud pop and the wire explodes back into the tip, then when the arc has started feeds normally, it happened so often i just stopped cutting it off cause there was so many starts and stops there is about 1/4 spool on my shop floor.

[nickn372]

3/64 is actually .043 but an .045 tip is too small. I've had good success with using a 1/16 tip with the 3/64 wire. Also try to deglaze the aluminum plate with a wire wheel or flap disc. Even with the cleaning with acetone or etc it isn't generally enough for wire welding to break up the smooth glaze that aluminum plate has to make a descent weld. My 2 cents.

[Oddjob83]

ya know i usually do wire wheel everything before i start. was running on an hour and a half of sleep today, guess it didn't occur to me, today was the first time I've tried to chemical clean it too, guess i was more focused on that. the plates i cleaned would give me a browner more smokey soot, and the uncleaned plates outright black. it would all wipe off with a dry cloth though too. the soot was really only a concern on corners, but there were a lot of them lol.

[Oddjob83]

ok so this will quickly become a close to 800+ post job as well as a panel between each post of 1.5x1.5x1/8" aluminum angle. with the added cleaning of each weld, would this be more feasible to just tig everything? all the panels I have to do onsite for custom fit ups around machinery. for now the plan is to go to the site with my LE 255 with spool gun and do all the mitered corners with some .030 wire, I'll either be under a tent or in a trailer as welding in the factory could cause explosions that could level the whole plant.

EDIT: I should also note that my only power at this remote building is a 220 30A plug. So if my big machine wont really work spooling 1/8 Aluminum would an inverter tig machine be more realistic or even possible.

[Otto Nobedder]

You'll be faster and more efficient with the spool gun, even with the post-weld cleanup.

To TIG anywhere near as fast, you'll need helium mix, which is expensive for most folk.

If this job is that big, can you justify a push-pull rig? Big problem solver, i'd think.

Steve S